Improvement in instruments for taking soundings



- UNITED STATES` PATENT fOEEIcE.

JOHN ERICSSON, OF NEW YORK, N.

IMPROVEMENT IN INSTRUMENTS FOR TAKING SOUNDINGS.

Specification forming part of Letters Patent No. 40,028, dated September22, 1863.

To all whom it may concern:

Be it known that I, JOHN ERICSSON, ofthe city, county, and State of NewYork, have invented a new and Improved Instrument for Taking Soundings;and I do hereby declare that the following is a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming part of l this 'specication The object of thisinvention is that of taking soundings from vessels navigating shallowwaters without stopping or checking the speed of such vessels.

The principle is of a self-acting nature, the depth of water being atall times shown by a self-adjusting index. This remarkable and desirableproperty of my invention will be fully understood by the followingexplanation:

It is a well-known fact that there is a certain fixed relation betweenthe pressure and the depth of water, and that therefore if the pressureof the sea at a certain point below the surface be known that pressureaccurately indicates the depth. My invention is founded on thesephysical facts.

I inclose an elastic air-tight bag in a small metallic vessel attachedto a tow-line secured to the vessel. An india-rubber tube is connectedwith the bag by an air-tight joint. This tube is lashed to the saidtow-line with its upper end put in communication with an ordinarypressuregage. This pressure-gage I graduate in such a manner that itsdivisions correspond with the pressure produced by one foot column ofwater. The index of the gage, therefore, in place of showing, as usual,the number of pounds of pressure to which it is subjected, will showwhat column of water corresponds with the pressure within the gage. Inother words, the index will show how far the instrumentis immersed belowthe surface of the water. yThus by mere inspection the depth ofwater'may at all times be accurately ascertained without theinconvenient and inaccurate process of heaving the lead, as hitherto.

In the drawings, Figure l represents a 1ongitudinal section of theelastic bag and the metallic vessel which protects it. et is a bagcomposed of thin india-rubber, b, cylindrical vessel made of compositionmetal, open at one end; c, tube made of india-rubber, connected with theair-bag a, and the pressuregage placed on board of the vessel 5 d,tow-line to which the metallic vessel b isattached. This line, which ismade fast within the vessel, serves the twofold purpose of towing thebag with its protection and supporting the indiarubber tube.

Fig. 2 represents longitudinal section of forward part of a vessel. b isthe metallic protection ofthe air-bag; c, the air-tube, and d thetow-line made fast at a point, e, within the vessel, while the tube c isconnected with the pressure-gage f. This latter indicates, as

before described, the height of the column of water above the air-bag.gis an open pipe attached to the forward part of the vessel, throughwhich the tow-line and air-tube are put outboard.

The operation of the instrument will b e readily understood. When putoutboard, the weight of the protecting metallic vessel will carry theelastic airbag to the bottom, where it will be acted upon by thepressure ofthe water compressing the air within it until the internalpressure balances the hydrostatic pressure from without. The air-bagbeing in free communication with the gage on board by means of theindia-rubber tube, the pressure will be transmitted to the gage, theindex of which will accurately showV the depth Of water at the pointwhere the bag is lodged.

It is an important feature of this instrument that the quantity of airwithin the bag is not an element affecting the accuracy of theindication. All that is needed is that the volume of air in the bagshould be considerably greater than that of the tube. Another markedfeature is'the reliability of the indication. For want of air in the bagless depth may be indicated than really is the case; but under nocircumstances can the navigator be deceived by an indication of toogreat a depth.

The most important feature of the invention is, however, that theindication of depth is continuous, as it offers facilities for navigat'ing shallow or unknown waters hitherto unattainable. For ships of warthe instrument is indispensable, as it admits of soundings being takenunder the enemys fire without exposing the crew.

It is evident that the air-bag may be made of various forms` as also theprotecting-vessel which carries it to the bottom. It is also evidentthat the connection between the bag and the indicator may be made invarious Ways, and that the pressure-gage itself may be made of any formwhatever as long as it registers the pressure with accuracy. It is,moreover,

evident that the gage With its indicator may be placed anywhere withinthe vessel or on deck, and that the tow-line and tube may be passed overthe raii or through the vesselvs s1 e.

I do not, therefore, confine myself to form or particular arrangement;but

J. ERICSSON.

Witnesses M. M. LIVINGSTON, SAMUEL W. TAYLOR.

